Liquified gas refrigerant (for example chloro-fluoro-carbon ("CFC")) cooling systems are quite common place in today's world. Nearly every home and many automotives have a CFC cycle refrigerator/freezer, and many homes, office buildings and automotives have CFC cycle environmental cooling systems. During the normal operation of these systems, some of the oil necessary for the lubrication of the refrigerant compressor is mixed into the refrigerant and contaminates it. Water can also contaminate the refrigerant over time. If the refrigerant is to be reused or recycled, it must be cleaned of oil and water.
The present state of the art uses a mechanical oil separator to remove the oil and an absorbent to remove any water contamination of refrigerants. The oil separator is inefficient and the water absorber requires multiple passes and testing after each pass to determine how well the CFC has been cleaned. Applicant's method can be used with various polymers and desiccants; however, applicants have found that a block copolymer (styrene-ethylene/butylene-styrene) works best for oil removal, an example of which is Shell Chemical Company's Kraton G. Presently Kraton is being used in adhesives, sealants, and coatings. Messrs. Odani, Uchikura and Kurata have done work using kraton as an N-Hexane absorber in "Transport Solution of Gases and Vapors and Styrene-Butadiene Block Copolymers: Absorption and Desorption of N-Hexane Vapor" Macromol. Sci-phys. B17 (2), 337-354 (1980). However, applicants are the first to apply Kraton to sorbing oil from refrigerants.
Further, chloro-fluoro-carbons in the atmosphere have become a major environmental concern. Some of the cleaning methods, prior to applicant's invention, include a risk of release into the atmosphere. Further production of chloro-fluoro-carbons is anticipated to be severely curtailed in the near future. Recycling and cleaning existing supplies of contaminated refrigerant while maintaining integrity with respect to atmospheric release will become essential. The price of new chloro-fluoro-carbons may become increasingly prohibitive as production is curtailed.
Applicant's invention overcomes the deficiencies of the prior art in providing a one pass cleaning system with various stages and filters to assure efficient and accurate cleaning of both oil and water contamination. By maintaining an enclosed system and limiting the number of passes and testing, this invention significantly reduces the risk of a leak to the atmosphere.